In addition to the constitutionality of the Speaker of the House inviting the Prime Minister of Israel to speak to the Congress, I can think of at least one other constitutional angle to the current foreign policy imbroglio–Zivotofsky v. Kerry.
This pending case is, in a sense, a microcosm of the feud going on between Congress and the President. Congress passed a law concerning the passports of American citizens who were born in Israel, because Congress did not approve of the foreign policy of the country. The previous President (who signed this law, ahem), argued that the statute violates the Separation of Powers. The current President contends further that a Supreme Court decision invalidating the law could frustrate the United States’s foreign policy interests. Foreign countries may become confused about how the United States views Israel. These points were made clearly by the Solicitor General during oral arguments.
It’s often hard to predict how current events can impact pending SCOTUS cases, but as this dispute heats up, I can see the Justices more likely to heed SG Verrilli’s admonition to stay out. It’s possible that the speech, and any resulting events, could sway the Justices to avoid getting entangled in this thicket. FantasySCOTUS tracks the daily predictions for the case. Let’s see if there is any motion.